When I go in drive, there is a loud, CLANK....

[fbodlovr]

Im not sure if this is the trans or the rear end. If I go into reverse, I dont hear the clank, but if I go into drive, I heard a CLANK. I'm pretty sure my rear end needs to be rebuilt because I can feel a shimmy when I am moving real slow, so i'm not sure if the rear end is just really screwed, and that is it, or maybe its the trans. What do you guys think?

 

[Boost231]

did you check your u joints? thats where i would start.

 

[overkillphil]

Assuming you have an LSD, when was the last time you changed the oil and GM additive in the rear?

 

[fbodlovr]

Thanks boost, I will check to see if that is it.

Over kill, I dont know what an LSD is. I have not driven this car on the road at all normally ever since I have had it in the past 5 years. Ever since i have had it I was trying to figure out an engine problem, but just decided to swap over to an intercooled setup, so thats where all my attention went. So, I have never changed it. As to the rear, I got the original sticker from allied vahn and it says it came with a posi if that helps.

From what I have read about the u joints, the clank I hear when I go into drive sounds correct. They also mentioned on a website you will feel a shake, and I do feel a small shimmy, like a really small back and forth kind of wabble when I am going real slow. Still think it could be those U joints? And where can I get new ones, and how hard to replace??

 

[theCATman]

Thanks boost, I will check to see if that is it.

Over kill, I dont know what an LSD is. I have not driven this car on the road at all normally ever since I have had it in the past 5 years. Ever since i have had it I was trying to figure out an engine problem, but just decided to swap over to an intercooled setup, so thats where all my attention went. So, I have never changed it. As to the rear, I got the original sticker from allied vahn and it says it came with a posi if that helps.

From what I have read about the u joints, the clank I hear when I go into drive sounds correct. They also mentioned on a website you will feel a shake, and I do feel a small shimmy, like a really small back and forth kind of wabble when I am going real slow. Still think it could be those U joints? And where can I get new ones, and how hard to replace??

LSD... limited slip differential.

 

[fbodlovr]

I remember the sheet saying posi, does that make a difference? I can check the sheet again. Let me know. Are you thinking the rear end is going to hell? The u joints seem to be a possible culprit.

 

[overkillphil]

No I'm thinking the additive is going to hell. It makes alot of racket and can feel like the rear is coming apart. And it's not an uncommon
phenomenon.

 

[theCATman]

The "clunk" sounds almost 100% a U-joint issue.

I was just letting you know what LSD stood for.

If the diff was low on oil, or posi additive in particular, it would growl or chatter when turning a sharp corner slowly. It wouldn't make any noise going in a straight line.

 

[fbodlovr]

Yeah. the clank sound is definitely that, a metal on metal, CLANK. lol Where can I get new u joints, and as well where can I get a rebuild kit for a posi rear end? I have had a wheel cylinder that was locking up when I put on the brakes, but once again, thats not where my attention has been. So might as well just do it in case. My dad saw some greese around the brakes and all that, and he thought the rear end was leaking somewhere around where the shaft comes out to the hub, and was making it lock up.

I guess what are your thoughts on that as well, and where can I get all these parts? Should I just get a whole new carrier assembly, or no since the car is able to move still?

 

[theCATman]

Any NAPA, Carquest, etc. will have U-joints. Get heavy duty ones. Spicer brand would be one of the best if they carry them.

The rear end is more than likely fine as far as parts go. Just change out the oil & posi additive. Unless of course a seal is bad & leaking oil. Clean everything up good with Brake-Kleen and then monitor the car after every drive to see where the oil leak is coming from.

 

[fbodlovr]

Ive got a question to follow up on this. I jacked the car up yesterday to look at the driveshaft where it meets the rear end. I put the car in neutral and was hand turning the tire to spin the drive shaft, and it seemed like everything was solid as far as wiggling the driveshaft and everything goes. I tried movied it back and forth a lot to see if there was any slop or anything like that in the u joint, and it seemed solid. Would I be able to see it somewhat flopping around if the u joint was bad as the driveshaft turned?

And this is another pertaining to the rear end. When I was turning the pass. tire, the drivers side tires was spinning the same way as the pass side. But when I started moving it back and forth rapidly, the other didnt move, almost like it was slipping or something, and it acted like it wanted to go the other direction when I was doing that rapidly. But If I turned the tire slowly, the other would go in the same direction. Does that sound right?

Im scared to buy u joints if the are ok, when there might be something else making the loud clank sound when it goes into drive. Could there be a lot of slack/slop somewhere else possibly? It sounded like a gear running into another for some reason.